Electronic devices for monitoring a patient's vital signs at bedside are in common use in hospitals. Typically these measure, display and transmit to nursing stations EKG traces, blood pressure values, body temperature values, respiration rates and other vitals. To accomplish this, sensors such as EKG pads, pressure cuffs, thermometers, etc. are attached to the patient by multiple leads. Each of the different devices is designed for use on a patient with limited mobility in a stable environment. In addition there are monitoring devices for heart rate, respiration and body temperature, designed for use by athletes, pilots, astronauts, etc. Some of the systems employ wireless transmission to a monitor. Again, these devices are designed for use in predictable environmental situations often where low cost and low transmission bandwidth are not limiting factors. These devices for the most part report detailed data such as full EKG trace details, although some merely have alarm functions if certain parameters are exceeded.
There has long been desired a reliable, reasonably low cost system for monitoring and aiding in the triaging of wounded soldiers in a battlefield environment, or triaging multiple trauma victims at an accident site. In particular the devices do not exist that could be worn by a soldier in the chaotic battlefield environment to provide enough useful information on vitals to say with confidence that the soldier is beyond the point where medical intervention would be useful, so as to be able to avoid or terminate rescue attempts that place a rescuer's life in jeopardy. Thus medics and other rescue personnel continue to be killed or seriously injured attempting to rescue soldiers where rescue was already hopeless. Despite the great need for systems to avoid such unnecessary casualties there has heretofore been no satisfactory system economical enough to simultaneously monitor large numbers of armed forces.
Such a system would also obviously be useful in non-military chaotic situations. For example ambulances and emergency vehicles are often equipped with personnel and diagnostic equipment that can be overwhelmed in situations where there are several injured to treat simultaneously. Again, there is not available at reasonable cost health assessment systems that could be applied to multiple subjects to allow triaging to take place rapidly by persons remote from the scene of injury.
Suggestions have been made as to how such systems should be organized and what should be measured. Nevertheless, despite these suggestions and the great need, the prior art has not advanced to the point where such systems have been built and made practical.
Prior patents that may relate to the problems of health state assessment are the following:
Respiration Effort Sensors
U.S. Pat. No. 5,513,646 entitled “Personal Security Monitoring System and Method” discloses a breath detector and a signal processor where the signal processor distinguishes between the user's normal breathing patterns and other patterns that trigger alarms.
U.S. Pat. No. 5,611,349 entitled “Respiration Monitor with Simplified Breath Detector” discloses a pneumatic breath detector using a low pass filter to reduce signals not indicative of respiration.
U.S. Pat. No. 6,377,185 entitled “Apparatus and Method for Reducing Power Consumption in Physiological Condition Monitors” discloses using a high power mode when data is written and a low power mode when inactive. Incoming data is placed in a low power buffer and transferred in a single data transfer.
U.S. Pat. No. 5,331,968 entitled “Inductive Plethysmographic Transducers and Electronic Circuitry Therefor” discloses such a device where the circuitry is located remotely rather than on a transducer.
U.S. patent application 2002/0032386 entitled “Systems and Methods for Ambulatory Monitoring of Physiological Signs” discloses monitoring apparel with attached sensors for pulmonary and cardiac function by including ECG leads and a plethysmographic sensor. Data from the sensors is stored in a computer readable medium for later use by health care providers.
Sensors and Signal Processors for Extracting a Physiological Measurement, Especially in a High Noise or High Motion Environment
U.S. Pat. No. 6,520,918 entitled “Method and Device for Measuring Systolic and Diastolic Blood Pressure and Heart Rate in an Environment with Extreme Levels of Noise and Vibrations” discloses using an acoustic sensor on the patient near an artery and a second acoustic transducer away from the artery. The signal of the first sensor is processed using an adaptive interfere canceller algorithm with the signal of the second acoustic sensor as interferer.
U.S. Pat. No. 6,629,937 entitled “System for Processing Audio, Video and Other Data for Medical Diagnosis and Other Applications” discloses a system for storing acoustic data in a file associated with a patient's medical record, which are analyzed to determine physiologically significant features useful in medical diagnosis based on an automatic analysis.
U.S. Pat. No. 5,853,005 entitled “Acoustic Monitoring System” discloses a transducer that monitors acoustic signals representative of heartbeat or breathing and transferred into a fluid. A comparison is made with predetermined reference patterns.
U.S. Pat. No. 6,616,613 entitled “Physiological Signal Monitoring System” discloses a system for determining blood pressure, heart rate, temperature, respiratory rate, and arterial compliance on the basis of signal characteristics of the systolic wave pulse. The systolic reflected wave pulse contour is subtracted from the digital volume pulse contour.
U.S. Pat. No. 6,200,270 entitled “Sensor for Non-Invasive and Continuous Determination of the Duration of Arterial Pulse Waves” discloses two spaced apart piezoelectric pressure sensors along the artery.
Wireless Networks—Low Power Digital Data Networks in the “Body Area” or “Personal Area” Space; Selectable Data Rates, Data Buffering and Store and Forward Means
U.S. Pat. No. 6,577,893 entitled “Wireless Medical Diagnosis and Monitoring Equipment” discloses wireless electrodes attached to the surface of the skin of a patient and having a digital transmitting and receiving unit.
U.S. Pat. No. 5,755,230 entitled “Wireless EEG System for Effective Auditory Evoked Response” discloses an electrode array for attachment to a person that senses voltages produced by brain electrical activity. An operator interface records a verbal stimulus and provides a comparison of the brain activity with the stimulus.
U.S. Pat. No. 6,167,258 entitled “Programmable Wireless Data Acquisition System” discloses such a data collecting system where a transmitting device can receive multiple inputs and transmit a signal encoded with data corresponding to the inputs.
U.S. Pat. No. 6,223,061 entitled “Apparatus for Low Power Radio Communications” discloses such a system controlled frequency modulation where a phase lock loop synthesizer is set to an open loop state to allow FM unimpeded by the normal frequency correcting action of the synthesizer.
U.S. patent application 2002/0091785 entitled “Intelligent Data Network” provides two-way communication between a node and a master device by pausing to listen after each transmission.
U.S. Pat. No. 6,450,953 entitled “Portable Signal Transfer Unit” discloses a system for relaying physiological data employing a memory for buffering the signal and wirelessly transmitting it to a remote unit.
U.S. Pat. No. 6,454,708 entitled “Portable Remote Patient Telemonitoring System Using a Memory Card or Smart Card” discloses a system that records full waveform data on smart cards. The system uses cordless, disposable sensors.
Systems for Remote Monitoring of Personnel
U.S. Pat. No. 6,579,231 entitled “Personal Medical Monitoring Unit and System” discloses a portable unit worn by a patient that stores physiological data and issues medical alarm conditions via wireless communications. The unit works with a central reporting system for long term collection and storage of the subjects data and can automatically dispense chemicals.
U.S. patent application 2002/0019586 entitled “Apparatus for Monitoring Health, Wellness and Fitness” discloses two sensors coupled to a processor and a memory for storing the data, which is subsequently transmitted.
U.S. Pat. No. 6,605,038 entitled “System for Monitoring Health, Wellness and Fitness” discloses a sensor worn on the upper arm including an accelerometer, GSR sensor and heat flux sensor. A central monitoring unit generates analytical status data that is transmitted to a recipient.
U.S. Pat. No. 6,160,478 entitled “Wireless Health Monitoring System” discloses a system for remotely monitoring a person's physical activity through use of an accelerometer. It may be used to determine whether a person has fallen and the likely severity of the fall and trigger an alarm.
U.S. Pat. No. 6,611,206 entitled “Automatic System for Monitoring Independent Person Requiring Occasional Assistance” discloses monitoring independent signals and combining them into a single alarm for possible intervention by a supervisor.
U.S. Pat. No. 6,198,394 entitled “System for Remote Monitoring of Personnel” discloses sensors disposable on a soldier that communicate with a soldier unit that can process the information to ensure that it falls within acceptable ranges and communicate with remote monitors. Body surface and ambient temperature are monitored. The inflammation may be stored and kept with the soldier to enable improved care as the soldier is moved to higher levels of care.
U.S. Pat. No. 6,433,690 entitled “Elderly Fall Monitoring Method and Device” discloses a system for recording acceleration and body position data from elderly or disabled persons. It detects health and life threatening falls and notifies nursing personnel of the need for assistance.
U.S. Pat. No. 6,416,471 entitled “Portable Remote Patient Telemonitoring System” discloses a system for transferring the full waveform ECG, full waveform respiration, skin temperature and motion data to a transfer unit worn by the patient on a belt for subsequent transfer to a monitoring base station where clinical data can be compared against given profiles.
U.S. Pat. No. 6,559,620 entitled “System and Method for Remote Monitoring Utilizing a Rechargeable Battery” discloses using such a battery in a system for remotely monitoring a person's position by GPS satellite.
Wearable Physiological Sensor Arrays and Processing Means Therefor (Vests, Straps, Adhesive Arrays, Etc.)
U.S. Pat. No. 6,527,711 entitled “Wearable Human Physiological Data Sensors and Reporting System Therefor” discloses a series of rigid and flexible pods within which sensors and computing apparatus are housed. The system allows relative movement of the rigid sections with respect to each other.
U.S. Pat. No. 6,494,829 entitled “Physiological Sensor Array” discloses a system for transmitting sensor output. Respiration is detected by a bend sensor.
U.S. patent application 2003/0105403 entitled “Wireless ECG System” discloses a cardiac monitor for a patient that transmits signals digitally to a remote base station, which converts the signals back to analog electrical signals to be read by an ECG monitor.
Sensors for Use in Physiological Monitoring (Temperature, Body Position, Blood Pressure, EKG or Heart Rate), Especially Under Exercise Conditions
U.S. Pat. No. 5,168,874 entitled “Wireless Electrode Structure for Use in Patient Monitoring System” discloses a wireless patient monitoring system using a patch electrode having a micro-chip amplifier on one side of the patch electrode.
U.S. Pat. No. 5,622,180 entitled “Device for Measuring Heartbeat Rate” discloses a wrist strap with skin contact electrodes such that signals from a skin sensor are filtered and pulse shaped for display.
U.S. Pat. No. 5,976,083 entitled “Portable Aerobic Fitness Monitor for Walking and Running” discloses a system for calculating the fitness of a person using personal data and comparing that data to pedometer and heart rate values generated during exercise.
U.S. Pat. No. 4,566,461 entitled “Health Fitness Monitor” discloses a heart rate monitor for use in aerobic exercise that calculates a fitness parameter by monitoring heart rate as the subject paces through an exercise stress test protocol. The system emits beeps that the subject matches to its stride frequency. At the point of exhaustion the maximal oxygen uptake capacity is determined and is displayed.
U.S. Pat. No. 5,544,661 entitled “Real Time Ambulatory Patient Monitor” discloses a patient monitoring system including an ECG and a photo-plethysmograph, arrhythmia analysis apparatus and an expert system for determining if a pre-established critical parameter set has been exceeded. When alarmed the ECG waveform and trends are transmitted to a clinician.
U.S. Pat. No. 6,236,882 entitled “Noise Rejection for Monitoring ECGs” discloses a looping memory for storing triggered physiologic events (such as arrhythmias and syncopal events) with auto triggers to record the ECGs. Denial and extensible accommodation periods are introduced in the R-wave sensing registration for triggering data storage.
U.S. Pat. No. 5,743,269 entitled “Cardiotachometer” discloses a system for computing a heart rate from ECG signals and encoding the signals for transmission to avoid erroneous reception of signals generated by noise or interference.